The command line

Everything Cobalt Photo does to many pictures at once, from a console, a .bat file or your own program — with the same formats, quality and care as its windows. No window opens.

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cobaltphoto convert *.heic --to jpg
cobaltphoto resize D:\Site -r --long 1600 --replace
cobaltphoto find D:\Photos -r "stars:5 taken:2025" | cobaltphoto pdf --name "Best of 2025"

Start

The command comes with Cobalt Photo: type cobaltphoto in Command Prompt, PowerShell, Windows Terminal or a .bat file, in any folder. Windows makes it known to every console itself; nothing to set up or add to the path.

• cobaltphoto alone, or cobaltphoto /?, lists every command.
• cobaltphoto convert /? — or any other command — gives that command's options and examples.
• The help and the messages are in the language of Settings → General; the commands and options are the same in every language.

It is a console program: it opens no window and shows nothing in the taskbar. To turn the command off, Windows has Settings → Apps → Advanced app settings → App execution aliases, cobaltphoto.exe.

Files and folders

After the command come the pictures, as many as needed, in any mix:

It reads every picture Cobalt Photo opens: JPG, PNG, HEIC, WebP, AVIF, JPEG XL, TIFF, GIF, BMP, ICO, SVG, Photoshop, Krita, OpenRaster, TGA, macOS icons and the RAW files of over 600 cameras — all formats. Hidden and system files are left out, as Explorer does. A path in quotes may have spaces.

Options of every command

convert — into another format

cobaltphoto convert <files> --to <format> [options]

The same as Convert: each picture upright, in the format asked for, next to the original or into -o. A RAW file's picture goes into a folder of the format's name beside it (JPEG), so it is not taken for the camera's own JPEG. The original is never changed. The place it was taken is never kept.

cobaltphoto convert *.heic --to jpg
cobaltphoto convert D:\Shots -r --to webp --long 1600 --mark "© Anna" -o D:\Web
cobaltphoto convert logo.png --to ico --ico-sizes 16,32,48
cobaltphoto convert *.cr3 --develop --vivid --to tiff -o D:\Print

resize — smaller, or to an exact size

cobaltphoto resize <files> --long <pixels> | --percent <n> | --size <w>x<h> [options]

As the Manager's Resize: each picture in its own format, its data kept. Copies beside the originals with the size in their name (photo (1600 px).jpg), or into -o — or with --replace the originals themselves, the old ones to the Recycle Bin. A RAW file gets a JPG copy. An animation, an icon and a picture already that small are left as they are. Its options: --long, --percent, --size with --fit, --no-sharpen as for convert, and --quality for JPG.

cobaltphoto resize *.jpg --long 1600
cobaltphoto resize D:\Site -r --percent 50 --replace
cobaltphoto resize avatar.png --size 512x512 --fit crop

mail — smaller for mail

cobaltphoto mail <files> [--long <pixels>] [--quality 1–100]

The drop panel's Smaller for mail: a JPG small enough to send, large enough to look at, beside each picture as photo (small).jpg. The long side as in Settings (2048 as it comes), unless --long says.

cobaltphoto mail IMG_0412.heic IMG_0413.heic
cobaltphoto mail D:\Trip -o D:\ToSend

pdf — pictures into a PDF

cobaltphoto pdf <files> [--name <name>] [--page picture | a4 | letter] [--each]

One PDF of all the pictures, a page each, in the order given — named after their folder (or the one picture), or --name. With --each, one PDF per picture. Next to the first picture, or into -o.

cobaltphoto pdf scan*.jpg --name Contract --page a4
cobaltphoto pdf D:\Receipts --each -o D:\PDF

extract — frames and icon sizes

cobaltphoto extract <files> [--frame <n>] [--size <pixels>]

As the viewer's Save frame and Save size, as PNG with their transparency:

• An animated GIF, WebP or PNG: all its frames into a folder beside it, anim (frames) — or only frame --frame (counted from 1), beside it.
• An ICO, CUR or ICNS: all its sizes into app (sizes) — or only the size --size (its width), beside it.

cobaltphoto extract anim.gif
cobaltphoto extract anim.webp --frame 12
cobaltphoto extract app.icns --size 256 -o D:\Icons

clean — without personal data

cobaltphoto clean <files> [--location-only] [--replace]

As the Manager's Clean: who, where and with what is taken out — the location, the camera's serial number, the author, comments — and what the picture needs to look the same stays, its date too. A JPG, PNG or WebP is not encoded again: only its data is cut out, and the result must open as the same picture before it is written. Other formats get a clean JPG.

• As it comes: a copy, photo (clean).jpg, beside it or into -o.
• --location-only: only where it was taken.
• --replace: the file itself, the old one to the Recycle Bin. Its dates stay.

cobaltphoto clean *.jpg -o D:\ToSend
cobaltphoto clean D:\Blog -r --location-only --replace

rotate — turn or flip

cobaltphoto rotate <files> right | left | 180 | flip-h | flip-v

Free. The files themselves are turned, as the viewer turns them. A JPG keeps every pixel: only its orientation tag changes, which every viewer and Windows follow. PNG, TIFF, BMP and GIF are written again without loss. RAW files and SVG are left as they are.

cobaltphoto rotate IMG_0412.jpg right
cobaltphoto rotate scans\*.png 180

meta — stars, labels, tags, text, dates

cobaltphoto meta <files> [what to set]

As the Manager's Metadata. Written into JPG and PNG themselves; RAW, HEIC, TIFF and WebP get an .xmp beside them, which Lightroom, darktable and the Manager read too. Only what is asked for changes; an empty value removes it: --title "".

cobaltphoto meta best\*.jpg --stars 5 --label green
cobaltphoto meta *.cr3 --shift -1h
cobaltphoto meta D:\Trip -r --add-tags "Rome,2026" --author "Anna"

rename — new names from a pattern

cobaltphoto rename <files> --pattern "{date}_{n}" [options]

As the Manager's Rename. The pattern's words:

A word the picture has nothing for is left out with its _ or -. A name taken gets (2). The RAW file, .xmp, .aae and Live Photo .mov of the same name are renamed with the picture. Options: --date iso | compact | dots | month (2026-10-12, 20261012, 12.10.2026, 2026-10), --start 1, --digits 3, --per-day (numbers start again each day), --order taken | name, --no-file-date, --lower-ext (.JPG becomes .jpg).

cobaltphoto rename *.jpg --pattern "{date}_{place}_{n}" --dry-run
cobaltphoto rename D:\Trip --pattern "{country} {date} {n}"

import — from a card into the library

cobaltphoto import <card or folder> [options]

As the Manager's Import & sort: the pictures and videos copied into the library, into folders by date or by trip, each copy checked byte by byte, its dates kept. The ones imported before are left out; a shot's RAW and JPEG stay together. A camera card (a drive with DCIM) is read with all its folders; another folder with -r.

cobaltphoto import E:\ --layout trips
cobaltphoto import D:\Downloads --move --to D:\Photos

duplicates — the same pictures

cobaltphoto duplicates <folders> [--series very | quite | little] [--small]

As the Manager's Duplicates search: byte-for-byte copies and the same picture in another size or format — and with --series, shots of a series that are almost the same. It only lists them, each group with its pictures, the largest first; it deletes nothing — what to delete is yours to choose, in the Manager or from --json in a script of your own. --small takes pictures under 256 px too.

cobaltphoto duplicates D:\Photos -r
cobaltphoto duplicates D:\Photos D:\Downloads -r --json > duplicates.json

find — pictures by what they are

cobaltphoto find <folders> "<query>"

The Manager's search, in the same words. It prints the paths that match, one per line — for a file, or a pipe into another command. Without a folder, the current one.

cobaltphoto find D:\Photos -r "stars:5 taken:2025"
cobaltphoto find D:\Photos -r "gps:yes" | cobaltphoto clean --location-only
cobaltphoto find D:\Photos -r "type:raw taken:<2020" > old-raw.txt

info — what a picture is

cobaltphoto info <files> [--json]

Free. Its kind, size in pixels and bytes; when and with what it was taken (camera, lens, focal length, aperture, shutter, ISO); where, with the town and the height; its stars, label, tags, title and author; an animation's frames, an icon's sizes.

cobaltphoto info IMG_0412.jpg
cobaltphoto info D:\Trip -r --json > trip.json

wallpaper and lockscreen

cobaltphoto wallpaper <file> [--fit fill | fit | stretch | center | tile]
cobaltphoto lockscreen <file>

Free. One picture as the desktop background on every monitor (fill as it comes), or as the lock screen's picture. Any picture Cobalt Photo opens: it is made an upright JPG first, in Cobalt Photo's own folder, so the original can move or go.

What it writes

A line about what is about to be done, a line per file — ✓ with what was made, or ✗ with why not — then the summary: how many, how long, the sizes before and after. Under the lines a progress bar counts on: how far, how many of how many, how many failed, about how long is left. Windows Terminal shows the same progress on its tab and its button in the taskbar. When the output goes to a file or a pipe, there is no progress bar and no colour; find then writes the paths alone.

--json

One JSON object per line, nothing else on the output — for ConvertFrom-Json in PowerShell, jq, or any program. Letters outside English are written as \u escapes, so the lines read the same in any console.

Exit codes

In scripts

A .bat file that converts what is dropped on it and says when something failed:

@echo off
cobaltphoto convert %* --to jpg --long 2048 -o "%USERPROFILE%\Desktop\For mail"
if errorlevel 1 pause

PowerShell, reading the results:

$big = cobaltphoto info D:\Photos -r --json | ConvertFrom-Json | Where-Object { $_.width -ge 6000 }
$big | ForEach-Object { $_.file }

In Windows PowerShell 5.1, a pipe between two programs passes only English letters unless $OutputEncoding = [Text.Encoding]::UTF8 is set first; PowerShell 7, Command Prompt and --json need nothing.

Pro

rotate, info, wallpaper and lockscreen are always free, as the viewer is. The other commands are Cobalt Photo Pro's, as in the app's windows: open in the 14-day trial and with a subscription. Without it, such a command says so, does nothing and ends with code 3. A subscription just bought counts at once: the command asks the Microsoft Store when Pro looks closed.